Search

Valproic acid (VPA) is an older first-line antiepileptic drug with a complex pharmacokinetic (PK) profile, currently under investigation for several novel neurologic and non-neurologic indications. Our study objective was to design and validate a mechanistic model of VPA disposition in adults and children; and evaluate its predictive performance of drug-drug interactions (DDIs). This study expands upon existing physiologically based pharmacokinetic (PBPK) models for VPA by incorporating UGT enzyme kinetics and an advanced dissolution, absorption, and metabolism (ADAM) model for extended-release (ER) formulation. PBPK models for VPA IR and ER formulations were constructed using Simcyp Simulator (Version 15). First-order absorption was used for the immediate-release (IR) formulation and the ADAM model, including a controlled-release profile, for ER. Data from twenty-one published clinical studies were used to assess model performance. The model accurately predicted the concentration-time profiles of IR formulation for single-dose and steady-state doses ranging from 200mg to 1000mg. Similarly profiles were also simulated for ER formulation after a single-dose and steady-state doses of 500mg and 1000mg, respectively. In addition, simulated PK profiles agreed well with the observed data from studies in which VPA ER formulation was given to pediatric patients and VPA IR formulation to adult patients with cirrhosis. The model was further validated with individual adult data from a Phase I clinical trial consisting of eight cohorts after IV infusion of VPA with doses ranging from 15 to 150mg/kg. Co-administrations of VPA as an enzyme-inhibitor with victim drug phenytoin or lorazepam, as well as a substrate with enzyme inducer carbamazepine or phenobarbital, were simulated with the model to evaluate drug-drug interaction. The simulated serum concentration-time profiles were within the 5th and 95th percentiles, and the majority of the predicted area-under-the-curve (AUC) and peak plasma concentration (C max ) values were within 25% of the reported average values. The comprehensive VPA PBPK model defined by this study may be used to support dosage regimen optimization to improve the safety and efficacy profile of this agent under different scenarios., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Objective: Combined traumatic brain injury and hemorrhagic shock are highly lethal. Following injuries, the integrity of the blood-brain barrier can be impaired, contributing to secondary brain insults. The status of the blood-brain barrier represents a potential factor impacting long-term neurologic outcomes in combined injuries. Treatment strategies involving plasma-based resuscitation and valproic acid therapy have shown efficacy in this setting. We hypothesize that a component of this beneficial effect is related to blood-brain barrier preservation., Design: Following controlled traumatic brain injury, hemorrhagic shock, various resuscitation and treatment strategies were evaluated for their association with blood-brain barrier integrity. Analysis of gene expression profiles was performed using Porcine Gene ST 1.1 microarray. Pathway analysis was completed using network analysis tools (Gene Ontology, Ingenuity Pathway Analysis, and Parametric Gene Set Enrichment Analysis)., Subjects: Female Yorkshire swine were subjected to controlled traumatic brain injury and 2 hours of hemorrhagic shock (40% blood volume, mean arterial pressure 30-35 mmHg)., Interventions: Subjects were resuscitated with 1) normal saline, 2) fresh frozen plasma, 3) hetastarch, 4) fresh frozen plasma + valproic acid, or 5) hetastarch + valproic acid (n = 5 per group). After 6 hours of observation, brains were harvested for evaluation., Measurements and Main Results: Immunofluoroscopic evaluation of the traumatic brain injury site revealed significantly increased expression of tight-junction associated proteins (zona occludin-1, claudin-5) following combination therapy (fresh frozen plasma + valproic acid and hetastarch + valproic acid). The extracellular matrix protein laminin was found to have significantly improved expression with combination therapies. Pathway analysis indicated that valproic acid significantly modulated pathways involved in endothelial barrier function and cell signaling., Conclusions: Resuscitation with fresh frozen plasma results in improved expression of proteins essential for blood-brain barrier integrity. The addition of valproic acid provides significant improvement to these protein expression profiles. This is likely secondary to activation of key pathways related to endothelial functions.

Background: Cardiac reperfusion injury can have devastating consequences. Histone deacetylase (HDAC) inhibitors are potent cytoprotective agents, but their role in the prevention of cardiac injury remains ill-defined., Objective: We sought to determine the therapeutic potential of HDAC inhibitors in an in vitro model of cardiomyocyte hypoxia-reoxygenation (H/R)., Method: H9c2 cardiomyocytes were subjected to H/R and treated with various classspecific and pan-HDAC inhibitors in equal concentrations (5µM). Biological activity of inhibitors was determined, as a proxy for concentration adequacy, by Western blot for acetylated histone H3 and α-tubulin. Cell viability and cytotoxicity were measured by methyl thiazolyl tetrazolium and lactate dehydrogenase assays, respectively. Mechanistic studies were performed to better define the effects of the most effective agent, Tubastatin-A (Tub-A), on the phosphoinositide 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) pathway effectors, and on the degree of autophagy., Results: All inhibitors acetylated well-known target proteins (histone H3 and α-tubulin), suggesting that concentrations were adequate to induce a biological effect. Improved cell viability and decreased cell cytotoxicity were noted in cardiomyocytes exposed to Tub-A, whereas the cytoprotective effects of other HDAC inhibitors were inconsistent. Pro-survival mediators in the PI3K/mTOR pathway were up-regulated and the degree of autophagy was significantly attenuated in cells that were treated with Tub-A., Conclusion: HDAC inhibitors improve cell viability in a model of cardiomyocyte H/R, with Class IIb inhibition (Tub-A) demonstrating superior cellular-level potency and effectiveness. This effect is, at least in part, related to an increased expression of prosurvival mediators and a decreased degree of autophagy., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Background: We have previously shown that treatment with valproic acid (VPA) decreases brain lesion size in swine models of traumatic brain injury (TBI) and controlled hemorrhage. To translate this treatment into clinical practice, validation of drug efficacy and evaluation of pharmacologic properties in clinically realistic models of injury are necessary. In this study, we evaluate neurologic outcomes and perform pharmacokinetic analysis of a single dose of VPA in swine subjected to TBI, hemorrhagic shock, and visceral hemorrhage., Methods: Yorkshire swine (n = 5/cohort) were subjected to TBI, hemorrhagic shock, and polytrauma (liver and spleen injury, rib fracture, and rectus abdominis crush). Animals remained in hypovolemic shock for 2 hours before resuscitation with isotonic sodium chloride solution (ISCS; volume = 3× hemorrhage) or ISCS + VPA (150 mg/kg). Neurologic severity scores were assessed daily for 30 days, and brain lesion size was measured via magnetic resonance imaging on postinjury days (PID) 3 and 10. Serum samples were collected for pharmacokinetic analysis., Results: Shock severity and response to resuscitation were similar in both groups. Valproic acid-treated animals demonstrated significantly less neurologic impairment between PID 1 to 5 and smaller brain lesions on PID 3 (mean lesion size ± SEM, mm: ISCS = 4,956 ± 1,511 versus ISCS + VPA = 828 ± 279; p = 0.047). No significant difference in lesion size was identified between groups at PID 10 and all animals recovered to baseline neurologic function during the 30-day observation period. Animals treated with VPA had faster neurocognitive recovery (days to initiation of testing, mean ± SD: ISCS = 6.2 ± 1.6 vs ISCS + VPA = 3.6 ± 1.5; p = 0.002; days to task mastery: ISCS = 7.0 ± 1.0 vs ISCS + VPA = 4.8 ± 0.5; p = 0.03). The mean ± SD maximum VPA concentrations, area under the curve, and half-life were 145 ± 38.2 mg/L, 616 ± 150 hour·mg/L, and 1.70 ± 0.12 hours., Conclusions: In swine subjected to TBI, hemorrhagic shock, and polytrauma, VPA treatment is safe, decreases brain lesion size, and reduces neurologic injury compared to resuscitation with ISCS alone. These benefits are achieved at clinically translatable serum concentrations of VPA., Level of Evidence: Therapeutic (preclinical study).

Background: The feedback medical students receive during clinical rotations, traditionally verbal and not formally captured, plays a critical role in student development. This study evaluates written daily feedback given to students through a novel web-based feedback system., Methods: A Minute Feedback System was used to collect feedback given to medical students during their surgery clerkship from May 2015-April 2016. Using qualitative content analysis, feedback comments were categorized as: encouraging, corrective, specific, and nonspecific. Effective feedback was a combination of specific and either corrective or encouraging feedback; ineffective feedback contained only nonspecific comments; mediocre feedback contained elements of both effective and ineffective comments., Results: 3191 feedback requests were sent by medical students and 2029 faculty/resident feedback responses were received. The overall response rate was 62%. Nonspecific feedback comprised 80% of faculty, 83% of senior resident, and 78% of junior resident comments. Specific feedback was given by only 35% of faculty, 17% of senior residents, and 26% of junior residents. Faculty provided Effective feedback in only 16% of comments, senior residents 8%, and junior residents 17%. Mediocre feedback comprised 13% of faculty, 9% of senior resident, and 7% of junior resident comments. Ineffective feedback comprised 67% of all feedback: 60% of faculty, 72% of senior resident, and 68% of junior resident feedback., Conclusions: The majority of resident and faculty feedback to medical students using an electronic, email-based application during their surgery clerkship was nonspecific and encouraging and therefore of limited effectiveness. This presents an opportunity for resident/faculty development and education regarding optimal feedback techniques., (Copyright © 2017 Elsevier Inc. All rights reserved.)

: Trauma-induced coagulopathy is associated with adverse patient outcome. Animal models demonstrate that histone deacetylase inhibitors, such as valproic acid (VPA), improve survival following injury. While in-vivo data suggest that improved survival may in part be because of an attenuation of coagulopathy, it remains unknown whether this is a direct effect of the drug, or the establishment of an overall prosurvival phenotype. We thus conducted an ex-vivo experiment to determine if VPA has an effect on coagulation and platelet function. Ten swine were subjected to traumatic brain injury (TBI) and hemorrhagic shock (HS). Blood samples were drawn prior to TBI+HS insult (Healthy group) and 2 h following TBI+HS (Shock group). Samples were incubated with VPA or vehicle controls for 1 h. Platelet aggregation was analyzed via impedance aggregometry and coagulation was measured using thromboelastography. Addition of VPA to the healthy blood did not affect platelet aggregation or coagulation parameters. In shock blood, incubation with VPA significantly reduced collagen-(P = 0.050), arachidonic acid-(P = 0.005), and adenosine diphosphate-(P = 0.023) induced platelet aggregation. VPA also significantly increased the clot strength (P = 0.002) and clot formation rate (P = 0.011). This is the first study to investigate the effect of VPA on platelet function ex vivo. Our results suggest that VPA has no effect on normal blood, but it decreases platelet activation and improves clot dynamics (strength and rate of formation) in blood from shocked animals. This suggests that VPA is capable of exerting a selective platelet sparing effect while enhancing the clot integrity.

Journals fill several important roles within academic medicine, including building knowledge, validating quality of methods, and communicating research. This section provides an overview of these roles and highlights innovative approaches journals have taken to enhance dissemination of research. As journals move away from print formats and embrace web-based content, design-centered thinking will allow for engagement of a larger audience. Examples of recent efforts in this realm are provided, as well as simplified strategies for developing visual abstracts to improve dissemination via social media. Finally, we hone in on principles of learning and education which have driven these advances in multimedia-based communication in scientific research.

Hemorrhage is a common cause of death in the battlefield. Valproic acid (VPA) has been associated with improved outcomes in multiple models of trauma, when combined with isotonic fluid resuscitation. However, isotonic fluid administered in this setting is logistically impractical and may be associated with complications. In this study, we sought to evaluate the feasibility and immunologic impact of combining VPA treatment with low-volume hypertonic saline (HTS). In vivo: female Yorkshire swine were subjected to hemorrhage (40% total blood volume) and polytrauma (rib fracture and delayed liver injury). Animals were kept in shock for 30 minutes and resuscitated with (1) normal saline (NS, 3× hemorrhaged volume), (2) HTS (7.5% saline, 4 mL/kg), or (3) HTS + VPA (4 mg/kg; 150 mg/kg; n = 3/cohort). After 18 hours of observation, animals were euthanized and the lungs evaluated for acute injury and expression of myeloperoxidase (MPO) and caveolin-1 (Cav-1). In vitro: human umbilical vein endothelial cells (HUVECs) were exposed to anoxic conditions (5% CO 2 , 95% N 2 ) for 16 hours in (1) normosmotic, (2) hyperosmotic (400 mOsm), or (3) hyperosmotic + VPA (4 mM) media. Immunohistochemistry and Western blots were performed to determine Cav-1 expression. Lungs from VPA-treated animals demonstrated decreased acute injury, MPO expression, and endothelial expression of Cav-1 when compared to lungs from animals resuscitated with NS or HTS alone. Similarly, HUVECs cultured in hyperosmotic media containing VPA demonstrated decreased expression of Cav-1. This study demonstrates that combined treatment with VPA and HTS is a viable strategy in hemorrhagic shock and polytrauma. Attenuation of lung injury following VPA treatment may be related to modulation of the inflammatory response.

We have shown previously that fresh frozen plasma (FFP) and lyophilized plasma (LP) decrease brain lesion size and improve neurological recovery in a swine model of traumatic brain injury (TBI) and hemorrhagic shock (HS). In this study, we examine whether these findings can be validated in a clinically relevant model of severe TBI, HS, and polytrauma. Female Yorkshire swine were subjected to TBI (controlled cortical impact), hemorrhage (40% volume), grade III liver and splenic injuries, rib fracture, and rectus abdominis crush. The animals were maintained in a state of shock (mean arterial pressure 30-35 mm Hg) for 2 h, and then randomized to resuscitation with normal saline (NS), FFP, or LP (n = 5 swine/group). Animals were recovered and monitored for 30 d, during which time neurological recovery was assessed. Brain lesion sizes were measured via magnetic resonance imaging (MRI) on post-injury days (PID) three and 10. Animals were euthanized on PID 30. The severity of shock and response to resuscitation was similar in all groups. When compared with NS-treated animals, plasma-treated animals (FFP and LP) had significantly lower neurologic severity scores (PID 1-7) and a faster return to baseline neurological function. There was no significant difference in brain lesion sizes between groups. LP treatment was well tolerated and similar to FFP. In this clinically relevant large animal model of severe TBI, HS, and polytrauma, we have shown that plasma-based resuscitation strategies are safe and result in neurocognitive recovery that is faster than recovery after NS-based resuscitation.

Background: Anastomotic leak is a major source of morbidity in colorectal operations and has become an area of interest in performance metrics. It is unclear whether anastomotic leak is associated primarily with surgeons' technical performance or explained better by patient characteristics and institutional factors. We sought to establish if anastomotic leak could serve as a valid quality metric in colorectal operations by evaluating provider variation after adjusting for patient factors., Methods: We performed a retrospective cohort study of colorectal resection patients in the Michigan Surgical Quality Collaborative. Clinically relevant patient and operative factors were tested for association with anastomotic leak. Hierarchical logistic regression was used to derive risk-adjusted rates of anastomotic leak., Results: Of 9,192 colorectal resections, 244 (2.7%) had a documented anastomotic leak. The incidence of anastomotic leak was 3.0% for patients with pelvic anastomoses and 2.5% for those with intra-abdominal anastomoses. Multivariable analysis showed that a greater operative duration, male sex, body mass index >30 kg/m 2 , tobacco use, chronic immunosuppressive medications, thrombocytosis (platelet count >400 × 10 9 /L), and urgent/emergency operations were independently associated with anastomotic leak (C-statistic = 0.75). After accounting for patient and procedural risk factors, 5 hospitals had a significantly greater incidence of postoperative anastomotic leak., Conclusion: This population-based study shows that risk factors for anastomotic leak include male sex, obesity, tobacco use, immunosuppression, thrombocytosis, greater operative duration, and urgent/emergency operation; models including these factors predict most of the variation in anastomotic leak rates. This study suggests that anastomotic leak can serve as a valid metric that can identify opportunities for quality improvement., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Combined traumatic brain injury (TBI) and hemorrhagic shock (HS) is highly lethal. In previous models of combined TBI + HS, we showed that early resuscitation with fresh frozen plasma (FFP) improves neurologic outcomes. Delivering FFP, however, in austere environments is difficult. Lyophilized plasma (LP) is a logistically superior alternative to FFP, but data are limited regarding its efficacy for treatment of TBI. We conducted this study to determine the safety and long-term outcomes of early treatment with LP in a large animal model of TBI + HS., Methods: Adult anesthetized swine underwent TBI and volume-controlled hemorrhage (40% blood volume) concurrently. After 2 hours of shock, animals were randomized (n = 5 per /group) to FFP or LP (1× shed blood) treatment. Serial blood gases were drawn, and thromboelastography was performed on citrated, kaolin-activated whole-blood samples. Five hours after treatment, packed red blood cells were administered, and animals recovered. A 32-point Neurologic Severity Score was assessed daily for 30 days (0 = normal, 32 = most severe injury). Cognitive functions were tested by training animals to retrieve food from color-coded boxes. Brain lesion size was measured on serial magnetic resonance imaging, and an autopsy was performed at 30 days., Results: The severity of shock and the degree of resuscitation were similar in both groups. Administration of FFP and LP was well tolerated with no differences in reversal of shock or thromboelastography parameters. Animals in both groups displayed the worst Neurologic Severity Score on postoperative Day 1 with rapid recovery and return to baseline within 7 days of injury. Lesion size on Day 3 in FFP-treated animals was 645 ± 85 versus 219 ± 20 mm in LP-treated animals (p < 0.05). There were no differences in cognitive functions or delayed treatment-related complications., Conclusions: Early treatment with LP in TBI + HS is safe and provides neuroprotection that is comparable to FFP.

Background: High doses of the histone deacetylase inhibitor valproic acid (VPA, 150-400 mg/kg) improve outcomes in animal models of lethal insults. We are conducting a US Food and Drug Administration-approved Phase I, double-blind, placebo-controlled trial to evaluate the safety and tolerability of ascending doses of VPA in human volunteers. We hypothesized that VPA would induce significant changes in the proteome of healthy humans when given at doses lower than those used in prior animal studies., Methods: Peripheral blood mononuclear cells were obtained from three healthy subjects randomized to receive VPA (120 mg/kg over 1 hour) at baseline and at 4 and 8 hours following infusion. Detailed proteomic analysis was performed using 1D gel electrophoresis, liquid chromatography, and mass spectrometry. Proteins with differential expression were chosen for functional annotation and pathway analysis using Ingenuity Pathway Analysis (Qiagen GmbH, Hilden, Germany) and Panther Gene Ontology., Results: A total of 3,074 unique proteins were identified. The average number of proteins identified per sample was 1,716 ± 459. There were a total of 140 unique differentially expressed proteins (p < 0.05). There was a minor and inconsistent increase in histone and nonhistone protein acetylation. Functional annotation showed significant enrichment of apoptosis (p = 3.5E-43), cell death (p = 9.9E-72), proliferation of cells (p = 1.6E-40), dementia (p = 9.6E-40), amyloidosis (p = 6.3E-38), fatty acid metabolism (p = 4.6E-76), quantity of steroid (p = 4.2E-75), and cell movement (p = 1.9E-64)., Conclusions: Valproic acid induces significant changes to the proteome of healthy humans when given at a dose of 120 mg/kg. It alters the expression of key proteins and pathways, including those related to cell survival, without significant modification of protein acetylation. In the next part of the ongoing Phase I trial, we will study the effects of VPA on trauma patients in hemorrhagic shock., Level of Evidence: Therapeutic study, level V.

Background: We recently discovered that Tubastatin-A, a histone deacetylase (HDAC6) inhibitor, can improve survival in a rodent model of hemorrhagic shock (HS), but mechanisms remain poorly defined. In this study, we investigated whether Tubastatin-A could protect intestinal tight junction (TJ) in HS., Methods: In an in-vivo study with Wistar-Kyoto rats, the rats underwent HS (40% blood loss) followed by Tubastatin-A (70 mg/kg) treatment, without fluid resuscitation. The experimental groups were (1) sham (no hemorrhage, no treatment), (2) control (hemorrhage, without treatment), and (3) treatment (hemorrhage with Tubastatin-A administration). Six hours after hemorrhage, ileum was harvested. Whole cell lysate were analyzed for acetylated α-tubulin (Ac-tubulin), total tubulin, acetylated histone 3 at lysine 9 (Ac-H3K9), β-actin, claudin-3 and zonula occludens 1 (ZO-1) proteins by Western blot. Histological effects of Tubastatin-A on small bowel were examined. In an in-vitro study, human intestinal epithelial cells (Caco-2) were divided into three groups: (1) sham (normoxia), (2) control (anoxia, no treatment), and (3) treatment (anoxia, treatment with Tubastatin-A). After 12 hours in an anoxia chamber, the cells were examined for Ac-tubulin and Ac-H3K9, cellular viability, cytotoxicity, claudin-3 and ZO-1 protein expression, and transwell permeability study., Results: Tubastatin-A treatment significantly attenuated HS-induced decreases of Ac-tubulin, Ac-H3K9, ZO-1 and claudin-3 proteins in small bowel in-vivo (p < 0.05). In cultured Caco-2 cells, anoxia significantly decreased cellular viability (p < 0.001) and increased cytotoxicity (p < 0.001) compared to the sham group, while Tubastatin-A treatment offered significant protection (p < 0.0001). Moreover, expression of claudin-3 was markedly decreased in vitro compared to the sham group, whereas this was significantly attenuated by Tubastatin-A (p < 0.05). Finally, anoxia markedly increased the permeability of Caco-2 monolayer cells (p < 0.05), while Tubastatin-A significantly attenuated the alteration (p < 0.05)., Conclusion: Inhibition of HDAC6 can induce Ac-tubulin and Ac-H3K9, promote cellular viability, and prevent the loss of intestinal tight junction proteins during HS and anoxia.

Background: Seven isoforms of histone deacetylase Class III have been reported - Sirtuin (SIRT) 1-7. We recently demonstrated that EX-527, an inhibitor of SIRT1, reduces mortality in a mouse model of lethal-cecal-ligationand- puncture (CLP)-induced septic shock. Our present study was aimed at determining whether selective inhibition of SIRT2, with AGK2, would decrease animal death and attenuate the inflammatory response in a septic model., Methods: Experiment I: C57BL/6J mice were intraperitoneally given either AGK2 (82 mg/kg) in dimethyl sulfoxide (DMSO) or DMSO alone, and 2 h later subjected to CLP. Survival was monitored for 240 hours. Experiment II: mice treated the same way as Experiment I, were grouped into (i) DMSO vehicle, and (ii) AGK2, with sham mice (operating but without any treatment) serving as controls. Peritoneal fluid and peripheral blood were examined at 24 and 48 hours for cytokine production. Samples of blood at 48 h were also allocated to assess coagulability using Thrombelastography (TEG). Morphological changes of bone marrow were evaluated from long bones (femurs and tibias) with hematoxylin and eosin (H&E) staining. Bone marrow atrophy was quantified by a blinded pathologist. Experiment III: cytokines in supernatant of the cultured normal primary splenocytes were measured after the cells were stimulated by lipopolysaccharide and treated with or without AGK2 (10 µM) for 6 hours., Results: AGK2 significantly reduced mortality and decreased levels of cytokines in blood (TNF-α: 298.3±24.6 vs 26.8±2.8 pg/ml, p=0.0034; IL-6: 633.4±82.8 vs 232.6±133.0 pg/ml, p=0.0344) and peritoneal fluid (IL-6: 704.8±67.7 vs 391.4±98.5 pg/ml, p=0.033) compared to vehicle control. Also, AGK2 suppressed the TNF-α and IL-6 production in the cultured splenocytes (TNF-α: 68.1±6.4 vs 23.9±2.8 pg/ml, p=0.0009; IL-6: 73.1±4.2 vs 49.6±3.0 pg/ml; p=0.0051). The TEG data showed that the mice subjected to CLP displayed prolonged fibrin formation and fibrin cross-linkage time, slower clot formation, decreased platelet function, and clot rigidity. AGK2 treatment was associated with dramatic improvements in fibrin cross-linkage and clot formation times, without a significant impact on the clot initiation parameters or platelet function. Additionally, AGK2 significantly attenuated the bone marrow atrophy (58.3±6.5 vs 30.0±8.2%, p=0.0262)., Conclusion: Selective inhibition of SIRT2 significantly improves survival, and attenuates sepsis-associated "cytokine storm", coagulopathy, and bone marrow atrophy in a mouse model of lethal septic shock.